ESSENTIAL GRAMMAR REVIEW

For example the first relative clause, listed above, shows the relationship between the subject and its complement science and term By the functions and implications of these pronouns in

Review of relative clauses

A/ A relative clause is also known as an adjective clause It is a subordinate clause with the function of

modifying a noun/ noun phrase or a pronoun

Example:

1 Science (pure science) is a term which is used to denote systemized knowledge in any field

2 Applied science is the term that is used to refer to the search for practical uses of scientific knowledge

3 Neil Armstrong was the first person who walked on the Moon

4 Here, we should distinguish pure science from technology through which applications are realized

5 Newton whom many of us, scientists have respected used not to be a good student at all

6 Newton, whose discovery of the theory of gravity was very strange, has been the pioneer in MechanicsPhysics

7 The book of which the cover has been torn is a very famous one written by David Halliday

From the above examples, we can see that the noun phrases a term, the term, the first person; technology and Newton are respectively modified by relative clauses

1 which is used to denote systemized knowledge in any field.

2 that is used to refer to the search for practical uses of scientific knowledge.

3 who walked on the Moon

4 through which applications are realized.

5 whom many of us, scientists have respected

6 whose discovery of the theory of gravity was very strange

7 of which the cover has been torn

B/ You can easily realize that these clauses begin with which/ that/ which/ who/ whom/ whose These are called relative pronouns They function as pronouns, and at the same time, show the relationship between

the modified noun/pronoun and other elements in the sentence For example the first relative clause, listed

above, shows the relationship between the subject and its complement (science and term)

By the functions and implications of these pronouns in each the above sentences, we can classify them intogroups as in the following table

Types

Functio

* a relative pronoun replacing an objective noun can be omitted

C/ Having a look at the example one, the relative clause is very necessary for the meaningful existence of

the sentence because if we read the sentence - Science is a term, it would be very difficult for us to

understand what it means exactly: We know the word science and we know the word term but what is more

about this term in relation with science is actually what we need to know That’s why a relative clause in this

case works best Such a relative clause is called a restrictive relative clause This type of relative clause is sometimes known as defining relative clause

Quite differently, from the fifth relative clause from the list we can see that the relative clause does not affectmuch to the meaning of the whole sentence, with or without this clause, the sentence still makes sense to us

In this case, the presence of a relative clause is only to give some extra information about Newton; such a

relative clause is called a non-restrictive clause or sometimes non-defining relative clause.

Other differences between these two types of relative clauses are as follow:

• Non- defining clause is more common in written style

• Non- defining relative clause must be put between two commas, except when it is at the end

of the sentence (the full stop replaces the second comma)

• Pronoun that can not be used in a non-defining relative clause

D/ In example four, you can easily realize the preposition through be put in front of the pronoun which.

• Here, we should distinguish pure science from technology through which applications arerealized

It is easy to see that the sentence can be understood in a simpler way by splitting it into two simplesentences – Here, we should distinguish pure science from technology Applications can be realized through

technology Now, it is obvious that the preposition through does not at all accompany the pronoun which randomly, actually, it accompanies the noun technology that the relative pronoun which replaces Here, there is no change in position between the noun (now its replacing item) and its accompanying preposition

In another case – Newton from whom we have been learning used not to be a good student anyway – the

preposition from is once more considered to be accompanying the noun Newton and it is also put before the

pronoun whom (replacing Newton)

From both cases, it is deduced that, we can put a preposition in front of objective pronouns, and this makesthe sentence more formal However, it is noted that,

• If a preposition is put in front of a pronoun, the pronoun can not be omitted

• Prepositions can not be put in front of pronouns that and who

• If the preposition is a part of a phrasal verb, it can not separate from its main verb E.g The progress of science is the topic which/that/φ we are looking into.

• Such words as some, many, and most can go before of whom and of which in a non-defining

relative clause E.g The success of this theory is attributed to American scientists, many of whom did lose their lives for it.

Practice

Combine each of the following pairs of sentences into one sentence with a proper relative pronoun.

1 A group will carry out this investigation This group will be organized.

Participle phrases replacing relative clauses

II Participle

ing verb PI

I participle

_)

(

_)

(

In which the former is considered the active participle and the second is known as passive particle

A participle phrase is the one with the centre element being a participle

Example:

1 working with me

2 studying Physics last year

3 written by a famous scientist

4 clarified by the International Bureau of Weights and Measures

5 having been carefully conducted in the laboratory

6 being considered by the Government

2 Participles replacing relative clauses

From the above mentioned, it is deduced that each type of participle, therefore, will replace a correspondingrelative clause with the same grammatical implication (whether passive or active), basing on the form of theverb phrase in the relative clause

Consider the following examples (from Unit one)

1 Science (pure science) is a term which is used to denote systemized knowledge in any field

2 Applied science is the term that is used to refer to the search for practical uses of scientificknowledge

3 Neil Armstrong was the first person who walked on the Moon

4 Here, we should distinguish pure science from technology through which applications arerealized

5 Newton whom many of us, scientists have respected used not to be a good student at all

6 Newton, whose discovery of the theory of gravity was very strange, has been the pioneer inMechanics Physics

It is clearly seen that half of the above examples of relative clauses are active (3, 5, 6) and the other half arepassive (1, 2, 4)

However, not all relative clauses but the ones with relative pronoun in subject position can be replaced withparticiple phrases This is applicable to both types of relative clauses Hence, among the above relativeclauses, only the first three can be replaced

We have:

1 Science (pure science) is a term used to denote systemized knowledge in any field

2 Applied science is the term used to refer to the search for practical uses of scientific knowledge

3 Neil Armstrong was the first person walking on the Moon.*

These sentences will be interpreted basing on the context in which it appears:

As in the first two participle phrases, they are used to make definitions so the verbs in the correspondingrelative clauses must be in present tense while, in the last one, the tense of verb in the corresponding relativeclause must be the simple past tense (it is the action of the past)

Note

• The third case of relative clause can be replaced with a to- infinitive

• Relative clauses with intransitive verbs can not be replaced with –ed phrase

………

………

………

4 Field (physics) is the area that surrounds an object, in which a gravitational or electromagnetic force

is exerted on other objects

………

………

5 Galileo's astronomical discoveries and his work in mechanics foreshadowed the work of the century English mathematician and physicist Sir Isaac Newton, one of the greatest scientists whoever lived

………

………

6 German astronomer Johannes Kepler, who was born in 1571, is a key figure in the history of physics ………

………

………

7 In the next millennium, physicists may achieve a single overarching theory that explains how the four fundamental forces in the universe can be unified ………

………

………

8 Mankind will always be indebted to Einstein for the removal of the obstacles to our outlook which were involved in the primitive notions of absolute space and time ………

………

………

9 Newton stated his ideas in several published works, two of which, Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy, 1687) and Opticks (1704), are considered among the greatest scientific works ever produced ………

………

………

10 Newton, Sir Isaac (1642-1727), who is considered one of the most important scientists of all time, is an English physicist, mathematician, and natural philosopher ………

………

………

11 No other half-century in history has witnessed so revolutionary a transformation in man's view of the nature of the physical universe as the one through which we have just passed ………

………

………

12 Over the last 1,000 years the science of physics has enabled us to probe and understand the world of the very large—the stars and the galaxies that contain them—and, more recently, the world of the very small—the fundamental particles that make up matter and the forces that govern their interactions ………

………

………

………

13 Physicists believe the universe began about 12 billion years ago in a cosmic explosion which isknown as the big bang, when a magnificent dowry of energy appeared and converted to particles ofmatter.

………

………

………

17 The same spirit that characterized Einstein's unique scientific achievements also marked his attitude

in all human relations

In English, the very difference in word order from that in Vietnamese is the order of adjectives: In English,adjectives go before nouns to modify nouns regardless of some exceptions while it is opposite inVietnamese For example:

English: a successful experiment → Vietnamese: mét thÝ nghiÖm thµnh c«ng

And we have more than one type of adjectives and sometimes a group of adjectives at the same time modifyone noun; that is why we have to clarify which type of adjective should go first, and which last

English adjectives have the following normal rule of positioning:

size – general description – age – shape – colour – material – origin – purpose – participle Noun

Example: a small nice old square brown wooden French writing desk (mét c¸i bµn viÕt cò b»ng gç nhá xinh

Relative clauses with relative adverbs

1/ A review on relative clauses with relative adverbs.

Example

a) The laboratory where experiments are conducted must be kept clean all the time

b) The time when we should conduct the experiment has not been decided yet

c) That Physics studies both universe and human being is the reason why I choose it to study for mylife

Each of the above sentences has a relative clause starting with a relative adverb:

a) where experiments are conducted

b) when we should conduct the experiment

c) why I choose it to study for my life.

2/ From the examples, it is deduced that relative adverb

where is used to modify a nouns referring to a place;

when is used to modify the nouns referring to time; and

why is used to modify the noun reason.

3/ However, there is difference among these relative adverbs in forming defining and non- defining relative clauses

3.1 Non – defining relative clauses

When and where are used in non- defining relative clauses

Example

a) You have to read the report next week, when the meeting is chair- manned by the president of oursociety

b) The earth, where we are living, has always been a mystery objective for scientists

c) Last year, when he got help from sponsors, was the most successful year for him since the start ofhis study in mechanics

3.2 Defining clause

a/ When and where are used in defining relative clauses, but each of these clauses modifies a special

group of nouns

• When follows the word time or other time notion as day, week, month, year

Example:

1 The time when we make the observations must be long enough

2 The day when I started the first lesson on Physics was very impressive

3 1642 is the year when Newton, Sir Isaac was born

Note

Adverb When can be replaced with pronoun which and an appropriate preposition such as in, at or

on.

The above examples can be rewritten in this way:

1 The time during which we make the observations must be long enough.

2 The day on which I started the first lesson on Physics was very impressive.

3 1642 is the year in which Newton, Sir Isaac was born.

• Where follows the word place or other words referring to a place such as room

or street and the two words situation and stage

Example:

1 The place where we do experiment is called a laboratory

2 The room where lectures are given is called the lecture hall

Note

Adverb where can be replaced with pronoun which and an appropriate preposition.

The above examples can be rewritten in this way:

1 The place in which we do experiment is called a laboratory

2 The room in which lectures are given is called the lecture hall

b/ Adverb why follows the noun reason

Example

1 The reason why you did not succeed was because you had not well prepared for it

2 Their conservations are the reason why they failed

Participle adjectives

Each English verb has two participles which can function as adjectives, present participle beingactive adjective, and past participle being passive adjective This means, the present participle canmodify noun with the function that it can tell the feature of the noun itself while the past participletells something about the noun that comes from outside the noun

Example:

1 training program -> the program of training

2 sounding device -> the device for sounding

3 filtering paper -> the paper for filtering

4 given time -> the time which is given

5 measured block -> the block which has been measured

6 derived units -> the units which have been derived Practice

Exercise 1: Combine each of the following pairs of sentences into one sentence using an appropriate

relative adverb and the word given.

1 Our universe and human beings are studied in an area The area is science

Science………

2 It was the year 1704 In this year, Newton had his second famous works named Opticks published.

1704 was the year.………

3 You do experiments in a room We call that room a libratory

7 It was the year 1959 In this year, a yard was officially defined as being 0.9144 meter

The year 1959 was the year ………

8 It was in the year 1960 A new standard meter was found out, basing on light

wavelength

1960 was the year………

9 1983 was an important year In this year, standard meter was officially defined as the distance that lightwave can travel in a given time

There are ………

………

13 He failed to give correct answer to the question It is because he did not know how to convert the unit

of length in English system of measurements

Exercise 2: Give the appropriate form of the verb (either in present or past participle) to complete each of

the following sentences.

1 The (choose) ……… seven units in 1971 are defined as basics units

2 The (measure)……… jar is used when we want to measure the volume of irregular objects

3 The (travel) ……… path of any object can be measured

4 The conversion of English system of measurements confuses me I am thoroughly (confuse)

………

5 No one may attend the lecture except the (invite) ……… guests

6 The (exist)……… matter that makes scientists wonder is how to maintain natural resources

7 Physics is a very (stimulate) ……… subject because once you get your hands down to it, youstart to think hard of our universe and ourselves

8 The (freeze) ……….water has lower density than liquid water

9 Outstanding students always have (inquire)……… minds

10 The (contaminate) ……… air has great influence on the success of

Adverbial clauses of time, place and reason

An adverbial clause of time is a subordinate clause (dependent clause) in a complex sentence which startswith a conjunction of time An adverbial clause of time sets a time reference for the action mentioned by themain verb phrase in the main clause

Example:

a When we understood the law that governs all of those phenomena, we arrived at the conclusion.

b While you are conducting experiment in the laboratory, be careful with all types of acids because

you may get burned

c You should be well- prepared before any observation is made on a phenomenon.

Some common conjunctions of time: when; while; before; after; since; (un)till; now that; as soon as; whenever; any time; by the time;

Note that, as for before and after, they can not only function as conjunctions of time but also as prepositions

of time:

a He jumped to the conclusion before any of his classmates.

b He reached the conclusion after his teacher’s explanation.

2 Adverbial clauses of reason

An adverbial clause of reason is a subordinate clause in a complex sentence that starts with one of following

conjunctions: because, since, as

Example:

a Because he was too hurried to reach the conclusion, he omitted a lot of valuable evidence

b He was successful since he learned of patience

c As he is still a student, he is unable to provide himself with such an expensive piece of equipment

3 Adverbial clause of place

An adverbial clause of place is a subordinate clause in a complex sentence which starts with one of the

following conjunctions: wherever; anywhere; everywhere; and where.

Example:

a Wherever there are human beings, there are ways of measuring things

b Everywhere he goes, he takes along his own measuring tape

Practice

Exercise 1: Fill in each gap with one suitable conjunction of time, place or reason to form adverbial clause

of time, place and reason for each of the following sentences In some cases, there can be more than one choice.

1 ……… work is done on a body, there is a transfer of energy to the body, and so work can be said to beenergy in transit

2 ………… an electric current flows through a wire, two important effects can be observed

3 ………… satellites were used in geodesy, geodetic networks were typically no larger than anindividual country or continent

4 ………… an electric current flows through a wire, two important effects can be observed

5 ………….its name was changed in 1989, the agency announced that it would soon establish regionalmanufacturing technology centers to speed the spread of new technology

6 ……… a current begins to flow in a conductor, a field moves out from the conductor

7 ……… an electric current flows in a metallic conductor, the flow is in one direction only

8 ……… interferometer measures distances in terms of light waves, it permits the definition of the

standard meter in terms of the wavelength of light

9 ………NIST has unique data-gathering functions, it is the principal agent for the development offederal standards for automatic data processing techniques, for computer equipment, and for computerlanguages

10 ………some atoms combine to form solids, one or more electrons are often liberated and canmove with ease through the material

11 Egypt is ……… Clepsydra or water clock is believed to have originated.

12 The first scientific study of electrical and magnetic phenomena, however, did not appear until AD1600,

………the researches of the English physician William Gilbert were published

13 Work is also expended ……… a force accelerates a body, such as the acceleration of an airplanebecause of the thrust forces developed by its jet engines

14 Physics is ………… you can find answer to almost every phenomenon in nature

15 The strength of a magnetic field depends on how concentrated the flux is; …………there is a lot of fluxflowing, the field is strong

Exercise 2: Fill in the blank with each of the following given words Each word is used once.

Resonance

Resonance is an important (1) phenomenon that can appear in a great(2) different situations A tragic example is the Tacoma Narrows bridge disaster This(3) bridge in Washington State, collapsed in a mild gale on 1 July 1940 The wind set uposcillating around the (4) which vibrated more and more violently until it broke up under the(5) The bridge had been in (6) for just four months; engineers learnt a lot about(7) oscillations can build up when a (8) structure is subject to repeatedforces

You will have observed a much more familiar (9) of resonance when pushing a smallchild on a swing; the swing + child has a natural frequency of oscillation; a small push each swing results inthe (10) increasing until the child swinging high in the air

Compound adjectives forming from participles

In Unit three, participles were introduced as adjectives In this unit, participles are considered as the stem informing compound adjectives

1/ Noun-participle -> compound adjective

 The structure that bears stress

 A pot for keeping water

 A device for measuring atmosphericpressure

 The pole that seeks north direction

 The jar that is used for measuringvolume

Passive (noun-PII) Explanation

Petrol-run engine

Book-based research

Research-based report

Nuclear waste-affected area

Physics law-governed phenomenon

 an engine which is run by petrol

 a research that is based on books

 a report which is made basing on research

 the area that is affected by nuclear waste

 a phenomenon which is governed by physicslaw

2/ adverb-participles -> compound adjectives

 the device that measures exactly

 the phenomenon that changes slowly

 the apparatus that operates efficiently

 the effect that spreads widely

 the scientist who works seriously

Carefully-conducted experiment

Regularly-made observation

Abruptly-activated behavior

Well-equipped laboratory

Negatively charged particle

 the experiment that is conducted carefully

 the observation that is made regularly

 the behavior that is activated abruptly

 the laboratory which is equipped wellthe particle that is negatively charged

Practice

Exercise 1: Form compound adjectives from participles, basing on the following explanations

Explanation

1 the objects that oscillate freely

2 the device that sounds echo

3 the devices which are used to conduct

experiments

4 the analyzer which describes in detail

5 the students who work industriously

6 the device which is used to develop

film

7 the graph that slopes upwards

8 the pole that points to the south

9 the system that transfers energy

10 the matter which is discussed heatedly

11 the waves that interfere destructively

 freely-oscillating objects

12 a report that is well presented

13 the particles that move fast

14 the capacitor that is made of silver

15 a current that decreases gradually

16 a ball that is thrown horizontally

17 a body that falls freely

18 the anode which is negatively charged

19 a magnetic field which is created by

electromagnetic coils

20 the device which is used for removing

water

Exercise 2: Fill in each of the gaps to complete the passage Each word is used once.

distinct light because attract photons experiments protons the

electromotive work same nevertheless particles forces

quantum mathematically actually absorbed experiences

For centuries, electricity and magnetism seemed (1)………… forces In the 1800s, however (2)………showed many connections between these two(3)………… In 1864 British physicist James Clerk Maxwelldrew together the(4) …………of many physicists to show that electricity and magnetism are(5) ………different aspects of the (6)………electromagnetic force This force causes (7)………with similarelectric charges to repel one another and particles with opposite charges to (8)……….one another.Maxwell also showed that (9)………….is a traveling form of electromagnetic energy The founders of (10)

……… mechanics took Maxwell’s work one step further In 1925 German-British physicist Max Born,and German physicists Ernst Pascual Jordan and Werner Heisenberg showed (11)……… thatpackets of light energy, later called (12)………., are emitted and (13)……….when chargedparticles attract or repel each other through the electromagnetic force

Noun clauses (1; 2)

A noun clause is the one which can function as a noun or noun phrase in a complex sentence and which

begins with conjunction that (1), an interrogative word (2) or conjunction if/whether (3).

Example:

1 We know that the very atoms and molecules of matter are continuously in motion

2 A rate tells how fast something happens, or how much something changes in a certain amount of time

3 On a straight and smooth road, we can not feel whether there is any change in your car’s speed

1 That- clause

A that-clause is the one that starts with ‘that’ This clause can function in the sentence as follows:

Subject: That all matters are made up of molecules, atoms and other micro bodies has been proven by

scientists

Direct object: We all know that every body is always in motion.

Subject complement: The assumption is that every body continues in its state of rest, or of uniform motion

in a right (straight) line (unless compelled to change the state by force impressed upon it) (Newton’s FirstLaw)

Appositive: Galileo’s assumption, that free-falling objects have the same value of acceleration, was proven

by himself with worldwide famous experiment at leaning Pisa Tower

Adjectival complement: We all know for sure that if we toss our key rings to the air, it will fall back to the

ground

Note: In informal use, ‘that’ is frequently omitted if that-clause functions as the object or the complement.

Thus, we may have:

I’m sure you can learn about motion easily

Direct object: Newton’s Second Law states how net force changes something’s velocity.

Subject complement: Matter’s resistance to a change in velocity is what we call inertia.

Appositive: Our plan, when the experiment is conducted, has not been approved yet.

Adjective complement: I’m not certain how the bonding force and the contact force work to hold you up

when you stand on firm ground

Prepositional complement: Frictional force between two solids also depends on how hard the two surfaces

press together

Note:

1 As regards meaning, these clauses resemble wh-questions in that they leave a gap of unknown ininformation, represented by the wh-element.

2 As for grammar, there is a similarity to wh-questions in that the wh-element is placed first’ indeed,apart from the absence of subject-operator inversion in the dependent clause, the structures of the twotypes of clauses are in all respects parallel We have, in the wh-interrogative clause, the same choicebetween initial and final preposition where the prepositional complement is the wh-element

Examples:

We can not decide on which design we should work first (formal)

or: We can not decide which matter we should work on first.

An infinitive wh-clause can be formed with all wh-words except why.

Example: The lecturer explained to us how to attack the problem.

1 Some common adjectives followed by a noun clause:

2 Some common nouns followed by a noun clause

3 Some common verbs followed by a noun clause

declare indicate (wh) recommend urge

request know(wh) remind wish

wonder (wh)

Note: Verbs with (wh) are those which can be followed by either a that-clause or wh-interrogative clause.

Practice

Combine each pair of sentences bellow into one sentence using the words given in brackets.

1 Motion is subject to three laws Newton himself showed this (that)

9 The word centripetal is an adjective used effectively in the case of circular motion It is important to

note this (that)

To express certainty (or to say that something is certainly true or untrue), we use will, must and can’t

1.1 For present and future situations, we use:

will, must and can’t + Verb base

In which:

a will is used when the speaker means that something is certainly true, even though we can

not see that it is true

Example:

1 He has finished his report on the spin-transfer effects ~ It’ll earn him world-wide fame.

2 If a body is at rest, It will remain at rest

Note: will is often used in its contracted form ‘ll

b Must is used when the speaker sees something as necessarily and logically true.

Example: The glass must attract the device.

The device must also attract the glass

You can see the contexts of the two above statements from the reading passage

c Can’t is used when the speaker sees it as logically impossible for something to be true Can’t and must are opposites.

Example: It can’t be explained how to measure mass by imagining a series of experiments ~ There must be

some experiments to be conducted

Or we can use:

will, must and can’t +be +V_ing

to lay emphasis on the continuation of the action.

Example:

1 Where’s Jane? ~ She’ll be working in the lab (I expect)

2 In general, if our standard body of 1kg mass has an acceleration a, we know that the force F must

be acting on it.

3 The ball can’t be moving It must be at rest because there’s no force acting on it

1.2 For a perfect situation, we use:

will, must and can’t + have +P II

Example:

1 The experiment will have been conducted by now

2 The ball is moving Someone must have kicked it

3 Newtonian mechanics can’t have worked in that case The interacting bodies were on the scale ofatomic structure

Note: In questions, we normally use can or will.

Example: Can it really be true?

How will it be done?

2 Possibility:

2.1 We use: may /might + verb base

to say that something is possibly true or an uncertain prediction.

Example:

1 We may find g by simply weighing a standard weight on a spring balance.

2 There might be an error somewhere in the procedures

Note: There is almost no difference in meaning, but may is a little stronger than might.

2.2 To lay emphasis on the continuation of the action, we can use

may /might + be + V_ing Example:

1 He may/might be doing well in Physics because he has borrowed a lot of books on Physics fromthe library

2.3 The perfect can be used also:

may /might + have + P II

Example:

1 He may/might have made a lot of observations before reaching such a conclusion

Note: These two verbs can not be used in questions Can and will are used, instead (Refer to (1))

For all the above verbs, we follow the rule of making negation or interrogation for modal verbs in general.Past perfect tense

Read the following passage:

The team of medieval physicists stepped out of the time machine and began to examine the strange, newdevice fastened to the window They had never before seen a suction cup, so with great enthusiasm, theybegan to experiment by pulling this mysterious device off the window, and then reattaching it

In the second sentence, the writer uses the past perfect tense of the verb to see to mean that this actionhappens before the actions expressed by to step and to begin which were conjugated in past tense This is theuse of the past perfect tense

We form the tense with: had + P II

To express an action or a state before a past time reference.

Examples: Everything had been good before he put his nose in.

Before quantum physics, the interacting bodies on the scale of atomic structure had not beenable to explain.

Practice

Exercise 1: Fill in the blank with will; can; must; can’t; may or might

1 Suppose that Earth pulls down on an apple with a force of 0.80N The apple _ then pull up onEarth with a force of 0.80N

2 A particle of mass m, located outside Earth a distance r from Earth’s center, is released, it _ falltowards the center of Earth

3 An object located on Earth’s surface anywhere except at the two poles _rotate in a circle about therotation axis and thus have a centripetal acceleration that points towards the center of thecircle

4 For an object situated in an underground laboratory, force of attraction be exerted on it by theinternal and external layers of the Earth

5 A body raised to a height h above the Earth possesses a potential energy of mgh However, this formula _ be used only when the height h is much smaller than the Earth’s radius.

6 How we ensure that a body thrown from the Earth will not return to the Earth?

7 In order for a body of mass m to break away from the Earth, it _ over- come a gravitationalpotential energy

8 Whenever a gravitational field changes appreciably in size and/or direction across the dimensions of abody, there be a tidal effect

9 Cardwell said:” High temperature superconductors – which are oxide in nature – containpredominantly copper, so this be a reasonable place to start”

10 The system is not working now There be something wrong with the engine

11 The limitations of volume as a measure of the amount of matter _ have been known to peoplemany centuries ago because they developed a method for measuring the amounts of differentsubstances independently of their volumes

12 The density of a mixture of two liquids usually depends on the ratio in which they are mixed The same

is true for the density of a solution of a solid in a liquid Thus, knowing the density of a liquid _ provide useful information

13 We _ depend on two properties alone to distinguish between substances This is particularlytrue if the measurements are not highly accurate

14 Perhaps, some substances that hardly dissolve in water _ dissolve easily in other liquids

15 You know, of course, from your own experience that you _ not mix together the products ofthe dry distillation of wood and get back anything resembling wood

16 Many reactions, like the reaction of copper with oxygen, are slow It is difficult in these cases to tellwhen all of one of the reacting substances has been used up Because the copper in your cruciblechanged to a black solid, you _have assumed that all the copper that was originally present inyour crucible had been reacted This have been an incorrect assumption, as the presence

of copper in the black substance has shown

17 Even with a high-powered microscope we can not see atoms, and so they _ be very small andthere _ be very many of them in any sample large enough for us to examine

18 Some pairs of elements form several compounds, whereas others form only one or even none (helium,for example, is not known to combine with any other element) There be some importantdifferences between the atoms of the various elements to account for their different behavior informing compounds.

Exercise 2: Put the verbs in brackets in its suitable tense.

This is what we were going on in our flying laboratory We (turn) _ on the jet engine by pressing abutton, and suddenly the objects surrounding us (seem) _ to come to life All bodies which (be made) fast were brought into motion The thermometer (fall) _down, the pendulum (begin) oscillating and, gradually coming to rest, assumed a vertical position, the pillow obediently (sag) _ under the weight of the valise lying on it Let us (take) a look at the instruments which(indicate) the direction in which our ship (start) accelerating Upwards, of course! Theinstruments (show) that we (choose) a motion with an acceleration of 9.8m/sec2, not verygreat, considering the possibilities of our ship Our sensations (be) _quite ordinary; we (feel) _ theway we did on Earth But why so? As before, we (be) - _ unimaginably far from gravitational masses,there (be) _no gravity, but objects (acquire) _ weight

The passive

Read the following two paragraphs:

Paragraph one: Sir Joseph John Thomson (1846-1940) is a British physicist and mathematician and was the

head of a group of researchers at Cavendish Laboratory in Cambridge Thompson discovered the electron

He is regarded as the founder of modern physics

Paragraph two: Electron is a subatomic particle and one of the basic constituents of matter The electron

was discovered by J.J Thomson It is found in all atoms and contains the smallest known negative electricalcharge

Compare the two sentences, one from each paragraph

Thomson discovered the electron

And The electron was discovered by Thomson

The two sentences have the same meaning but different topics: they are about different things, hence havingdifferent implications In the former one, the topic is Thomson while in the latter one the electron We saythe two sentences have different subjects So what is the significance of the difference between the two ways

of saying? The answer really lies in whether we want to lay emphasis on the doer of the action (we call it the

agent) or the action (sometimes the result of the action) itself.

In this pair of sentences, the first one is called an active sentence while the second is called passive sentence

Look at the verb phrase of each sentence: "discovered" and "was discovered"

Therefore, we deduce that the verb phrase in passive sentences is formed by combining the auxiliary verb to

be and a passive particle (exactly the same form as a part participle)

To be + P II

In which the auxiliary verb to be bears all the grammatical changes in tenses and aspects and others.

1 Present tenses:

a Many elements are not so easily identified.

b Once this has been done, however, the presence of that element has been definitely established.

c When the experiment is being conducted, there should be no changes in ambient

temperature

2 Past tenses:

a During the first five years of spectroscopy, five new elements were discovered that are present on earth in such small concentrations that they were previously unknown.

b This set of lines had never been seen before.

c Eventually, the element was also detected on earth through the use of a spectroscopy

d While the experiment was being conducted, the ambient temperature was kept unchanged.

3 With “modal verbs”: The passive sentences with modal verbs are formed as follows:

Modal verb + be + P II

a This may have given you the impression that only the spectrum of one of the element in a

compound can be observed.

b Spectral analysis, or spectroscopy, can be done on tiny quantities of matter.

c Spectroscopy can be even used to determine the presence of different elements in distant

objects like our sun and stars

d Most of the spectral lines observed in sunlight could also be produced with known materials

For example: The same volume of hydrogen is added to the tube.

2 From the sample paragraphs and all the examples taken out from the reading text, we candeduce that, in writing a science report or description, the use of passive sentences iscommonly resorted to And more commonly, the impersonal passive is used:

Have another look at the passive sentence in the pair of sentences taken out from the two sample paragraphs:

The electron was discovered by J.J Thomson

The underlined phrase is called by-phrase (forming by by + agent) This gives the new information (by

whom) to clarify the topic (subject) which is an already -known piece of information (the electron was

discovered) However, in science documents, the actions and their result are much more important, the phrase becomes little important, hence forming the impersonal passive to be frequently used.

by-In scientific documents, the following special patterns of passive are taken much use of:

1 The passive with get:

Instead of be, sometimes we use get to form passive sentences:

Example:

1 If the spring is stretched beyond its elastic limit, it will get deformed.

2 Everything gets attracted to the center of the earth no matter where they are.

3 When you do the experiment, be careful or you may get burned.

However, get is mainly used in informal English, and it has more limited use than be The passive with get

expresses action and change, not a state It often refers to something happening by accident, unexpectedly

or incidentally

2 The passive with verbs of reporting

There are two special patterns with verbs of reporting which are frequently used in science writing

Active: Long time ago, people believed that the earth had a round shape

Passive: Long time ago, it was believed that the earth had a round shape.

Long time ago, the Earth was believed to have a round shape.

Thus, we have:

Pattern one: It + passive verb + finite clause

More examples:

1 It is specified that gravitational potential is also a scalar.

2 It might be thought that the force needed to lift something is greater than its weight.

3 It has been proved that the force of gravity is an attractive force between any two objects

because of their masses

The following verbs are used in this pattern:

expect*

explainfeel*

find*

hopeintend*

know*

mentionnoticeobjectobserve*

presume*

promiseproposeprove*

recommendreport*

say*

see*

show*

specifystatesuggestsuppose*

think*

understand*

Pattern two: Subject + passive verb + to-infinitive

More examples:

1 Gravitational potential is shown to increase by drawing equipotential lines onto a diagram

of the field lines

2 It was about only 100 years ago that a way was discovered to separate aluminum from

oxygen by electrolysis

3 Acids were considered in the old days to be the substances that were strongly corrosive and

had a sour taste

The verbs which are used in this pattern are those with an asterisk (*) in the above list for pattern one Practice

Exercise 1: Change the following active sentences into the passive ones

1 We notice that the displacement changes between positive and negative values

9 We can not decompose the radioactive elements by ordinary heat, electricity, reaction with acids, andthe like

Exercise 2: Change the following passive sentences into their active equivalents

1 Today, many varieties of lasers are made using different atoms and molecular compounds in the solid,liquid, or gaseous states

13 Simple line spectra can be obtained from some gemstones and colored glass.

1 If you had worked carefully, you would have found that all the changes

in mass that you observed were within the experimental error of your equipment

Special patterns of comparison

You have learnt all the basic patterns of comparison of adjectives and adverbs The following will presentonly two common special patterns that are used quite a lot in science writing:

Pattern 1: the … + comparative … the … + comparative

This pattern is used to express a parallel increase or to say that a change in one thing goes with a change inanother

Example:

1 The greater the mass is, the larger the attraction gets.

2 The more careful you are when conducting the experiment, the better the results.

3 The more thoroughly you examine the phenomenon, the narrower the limitations of your

conclusion (will be)

Pattern 2: comparative and comparative

This pattern is used to express gradual and continuous decrease or increase

Example:

1 As you warm a piece of candle wax in your hand, it becomes softer and softer.

2 As the Earth recedes into the distance, the potential increases more and more slowly

2 we examine the works of a clock

3 one side of a block is rougher than

the other sides

a we will find that separatetrains of wheels drive the hour hand and theminute hand

b it is impossible to change itsmass, regardless of what external actions